Slickedit 2013 18.0.1.2 or so.
I floated a tab with source code in it, so I could look side-by-side. I rebooted the computer, and now that floating window is sitting, empty. I can find no way to unfloat it. How do I do this? Its title is "vs", but that wasn't the name of the file it had before.
Most notably, clicking its close box closes it and the main Slickedit window.